The way most of the commentaries on Match of the Day nowadays are added in afterwards. The commentator will more often than not come out with a relevant stat or comment just before a goal. Or they'll say, "Oh that looked like handball there", it didn't at first, but does after a couple of replays.
They're obviously at the game taking notes. They then do the post match interviews, then retire to a big truck to dub in the commentary, using hindsight to sound like a right smart arse. If you haven't noticed it, you might now.
It's petty, but it gets on my nerves.